1. Scope of Application and Purpose
This maintenance manual specifies procedures for regular inspection and testing of overhead cranes used in industrial production. It covers key components such as steel ropes, braking systems, limit switches and crane hooks. The goal is to ensure safe and reliable operation of the equipment, minimizing the risks of accidents and unplanned downtime. It is recommended that these procedures be performed as part of routine maintenance, before starting operation after a long period of inactivity, and after any repair work affecting the listed components.
2. Security measures
WARNING: Before starting any maintenance work on the bridge crane, you MUST apply the Lockout/Tagout - LOTO procedures in accordance with the company's internal standards and NPAOP 0.00-1.01-07. Check the absence of voltage on all electrical circuits supplying the faucet. Failure to follow this requirement could result in SERIOUS INJURY or DEATH due to electric shock or unexpected movement of the crane.
WARNING: When performing work, use the necessary personal protective equipment (PPE), including a hard hat, safety glasses, work gloves, safety shoes, and a safety system when working at height. There is a risk of falling from a height, entrapment of limbs by moving parts, and falling loads.
WARNING: Make sure that the working area around the crane is clear of other persons and objects. Fence off the danger zone. Never work under a raised load.
3. Necessary Tools and Materials
| Tool / Material | Specification | Quantity |
|---|---|---|
| A set of wrenches | Metric, from 8 mm to 32 mm | 1 set |
| Torque wrench | Range 10 - 200 Nm, calibrated | 1 pc. |
| Multimeter | Functions: measurement of voltage (AC/DC), resistance, ringing | 1 pc. |
| Vernier caliper | Range 0 – 150 mm, accuracy 0.02 mm | 1 pc. |
| Measuring tape measure | Length 5 m, metal | 1 pc. |
| Magnetic powder flaw detector (for NK hook) | With a set of test samples and calibration blocks | 1 set |
| Ultrasonic flaw detector (as an alternative to NC) | With a set of test samples and calibration blocks | 1 set |
| Lint-free napkins | Industrial | 1 package |
| Means for degreasing | Industrial, non-aggressive to metals | 1 vial |
| Grease for ropes | According to the manufacturer's recommendations, ISO VG 220 | 1 tube |
| Consistent lubricant | For bearings and hinges, according to the manufacturer's recommendations | 1 tube |
| Forms for checklists | Paper or electronic | According to need |
| Means of access (tower, lift) | Certified, with an active inspection | 1 pc. |
4. Checklist Before Service
Before starting the detailed procedures, it is necessary to conduct a preliminary visual inspection and check of the work area.
| Element | Verification | Acceptance/Rejection Criteria | Notes |
|---|---|---|---|
| Work permit | Availability and adequacy of instruction | The permit has been issued, all personnel have been instructed | |
| The LOTO system | Checking the installation of locks and tags | All energy sources are identified and blocked | |
| Work area | Absence of obstacles, foreign objects | The area is free for safe access and work | |
| Lighting | Sufficient lighting of all service areas | A minimum of 200 lux on the work surface | |
| Means of access | Functionality of stairs, platforms, lifts | Reliable fastening, no deformations, working mechanics | |
| General condition of the crane | Visual inspection of load-bearing structures for cracks, deformations, corrosion | Absence of visible damage, cracks in welds, excessive corrosion | |
| Crane hook | Visual inspection of the hook, safety latch | The latch works freely, without visible cracks or deformations | |
| Steel rope | Visual inspection of the condition of the rope in the visible area | Absence of obvious broken wires, bends |
5. Step-by-step Service Procedure
Step 1: Preparation and Complete Energy Isolation
- Notify about the start of work: Inform all interested parties (operators, workshop management) about the planned work.
- Move the crane: Stop the crane in a safe and serviceable area, preferably away from active production lines.
- Shutdown and Lockout: Turn off the main faucet breaker and apply LOTO procedures. Install interlock devices and warning tags on all power supplies. Mistake: Forgetting about auxiliary power sources such as lighting or auxiliary mechanisms.
- Check for no voltage: Using a multimeter, verify that there is no voltage at the input terminals of the main contactor and other electrical parts that will be accessed.
- Enclose the work area: Install boundary tapes or portable fences to prevent access by unauthorized persons.
Step 2: Detailed Inspection of Steel Rope
This procedure is performed in accordance with the requirements of DSTU EN 15011 and ISO 4309.
- Visual inspection of the entire length of the rope: Ensure full access to the rope (using a hoist or derrick). Carefully inspect the rope along its entire length, including the areas on the drum and through the blocks.
- Finding broken wires: Pay special attention to the sections that pass through the blocks and wind onto the drum. Measure the pitch of the rope bend (approximately 6-7 diameters of the rope). Rejection criterion: The number of visible broken wires exceeds 2 per coil step or 4 in the section 6d (where d is the nominal diameter of the rope). Bug: Ignoring broken wires, resulting in accelerated wear and sudden failure of the rope.
- Estimating Wear and Corrosion: Use a caliper to measure the actual diameter of the rope at several points. Deviation criterion: The reduction of the diameter of the rope exceeds 7% of the nominal. Inspect for signs of corrosion (rust, peeling). Error: Underestimation of internal corrosion, which is not always visible from the outside.
- Search for deformations: Check for deformations such as bends, kinks, flattening, "bird cages" (loose wires), core protrusions. Rejection criterion: The presence of any visible deformations that violate the geometry of the rope.
- Rope Lubrication: If the rope is dry or shows signs of slight corrosion, clean it and apply the manufacturer's recommended lubricant. Ensure even coverage.
Step 3: Testing the Braking System
- Visual inspection of brakes: Inspect brake pads (tapes), brake drums (discs), springs and drive mechanisms for wear, cracks, deformations, oil leaks. Rejection criterion: Uneven wear of pads, presence of cracks, damage to springs.
- Measuring the brake pad clearance: Measure the gap between the brake pads and the drum (disc) at several points using feelers. Acceptance criterion: Clearance 0.2 – 0.5 mm (according to DSTU EN 15011 and the instructions of the crane manufacturer). Error: Excessive clearance leads to increased braking distance, insufficient clearance leads to overheating and accelerated wear.
- Checking the operation of the braking mechanisms: Make sure that all hinges and levers move freely. Clean it of dirt, grease the joint joints with a consistent grease.
- Brake Functional Test: After all work is completed and power is restored (Step 6), perform a functional test. Lift the load (first without, then with the rated load) and check the stall speed and no slippage. Acceptance criterion: The braking distance does not exceed 5% of the working speed of the climb.
Step 4: Verification of Limit Switches
Limit switches are critical to the safe operation and prevention of crane damage.
- Location and visual inspection: Locate all limit switches (raise, lower, crane move, trolley move). Inspect them for mechanical damage, contamination, corrosion.
- Mechanical actuation check: Manually activate each limit switch. Make sure the firing mechanism moves freely and returns to its original position.
- Electrical check of contacts (with power off): Using a multimeter in resistance or ringing mode, check the integrity of the electrical contacts of the switch. Acceptance criterion: The resistance of closed contacts is no more than 0.1 Ohm, open contacts - infinity. Error: Dirty or oxidized contacts can cause the switch to malfunction.
- Setup and functional test (after power is restored): After power is restored (Step 6), check the operation of the limit switches while the crane is running with no load. Acceptance criterion: The upper position limit switch must stop the lift 50 mm ±10 mm to the maximum upper position of the hook (according to the manufacturer's instructions). The crane and trolley travel switches must operate before the buffers are reached.
Step 5: Non-Destructive Hook Inspection
It is performed in accordance with DSTU EN 13001-1 and other industry standards.
- Cleaning the surface of the hook: Thoroughly clean the surface of the hook from dirt, grease, paint with a degreaser and lint-free wipes. A clean surface is critical for the reliability of NC results.
- Measuring hook opening: Use a caliper to measure hook opening. Rejection criterion: Increase in opening of the hook by more than 10% from the initial size specified in the technical documentation.
- Magnetic Powder Inspection (MPI):
Use MPI to detect surface cracks. Apply magnetic powder to the cleaned surface of the hook and magnetize it. Observe the formation of indications. Rejection criterion: Presence of linear indications indicating cracks. Focus on the bend and transition areas from the body of the hook to the shank. Error: Insufficient magnetic field strength can cause defects to be missed.
- Ultrasonic inspection (USC) - as an alternative or addition:
Use ultrasound to detect internal defects. Scan the hook using the calibration blocks. Deviation criterion: Detection of echo signals from internal defects exceeding the permissible values according to regulatory documentation. Error: The wrong choice of sensor or frequency can reduce the effectiveness of defect detection.
- Documenting the results: Record all detected defects, their locations and sizes in the NC report.
6. Inspection Checklist After Service
After completing all the work and restoring power, it is necessary to check the correct functioning of the faucet.
| Test | Expected Result | Actual Result | Pass/Fail |
|---|---|---|---|
| General visual inspection | No visible damage, all covers and covers installed | ||
| Lifting/lowering test (no load) | Smooth movement, no extraneous noises, clear operation of limit switches | ||
| Lifting/lowering test (with minimum load) | Stable lift, effective braking, no slipping | ||
| Crane/trolley movement test | Smooth movement, activation of limit switches, no jerks | ||
| Braking system test | Fast and reliable stopping of the load, no slipping after stopping | ||
| Test of the emergency stop system | Instant complete stop of all movements of the crane | ||
| Inspection of the working area | Cleanliness, lack of tools and materials | ||
| LOTO withdrawal | All tags and locks are removed, the equipment is ready for operation |
7. Troubleshooting Guide
| Symptom | Probable Cause | Corrective Actions |
|---|---|---|
| The crane does not respond to commands | Lack of power; Activation of the emergency stop; Malfunction of the control panel. | Check the main switch and automatic switches; Reset the emergency stop button; Check the cable and remote control contacts. |
| The steel rope is sagging or has an uneven winding | Incorrect tension setting; Malfunction of guide rollers; Rope damage. | Adjust the rope tension; Check and replace guide rollers; Replace the damaged rope. |
| Brakes slipping or ineffective | Wear of brake pads; Incorrect gap adjustment; Contamination of friction surfaces with grease. | Replace brake pads; Adjust the gap (0.2-0.5 mm); Clean the braking surfaces, eliminate the leakage of lubricant. |
| Limit switches do not operate or operate incorrectly | Mechanical damage or contamination; Incorrect setting; Malfunction of electrical contacts. | Clean, repair or replace the switch; Check and adjust the position; Check the contacts with a multimeter. |
| The faucet makes unusual noises (creaking, vibration) | Bearing wear; Malfunction of the gearbox; Uneven wheel wear. | Localize the noise source; Check and replace bearings; Diagnose the gearbox; Check the condition and geometry of the running wheels. |
| The hook has cracks or significant deformations | Overloading; Material fatigue. | Immediately remove the crane from operation; Replace the hook. |
8. Recommended Maintenance Schedule
This schedule is based on standard recommendations and can be adapted depending on the intensity of operation and environmental conditions.
| Task | Frequency | Estimated Duration | Qualification Level |
|---|---|---|---|
| Daily visual inspection | Daily (before the start of the shift) | 10-15 minutes | Operator / Technician |
| Weekly inspection (brakes, limit switches) | Every week | 1-2 hours | Service technician |
| Monthly in-depth inspection (rope, lifting/moving mechanisms) | Every month | 4-6 hours | Certified technician |
| Quarterly inspection (electrical equipment, welds) | Quarterly | 6-8 hours | Electrician / Welder defect inspector |
| Annual full inspection (including NC, load test) | Annually | 8 a.m. to 4 p.m | NC specialist, certified engineer |
| Overhaul / Modernization | Depending on the condition, but not less often than every 10 years | According to the scope of work | A team of specialists |
9. Directory of Spare Parts
Having access to quality spare parts is critical to ensuring smooth operation of overhead cranes. UNITEC-D offers a wide range of components that meet international standards.
| Description Details | Typical Specification | Category UNITEC |
|---|---|---|
| Brake pads / Tapes | Material: friction composite; Dimensions: according to the model of the crane and brake mechanism | Braking systems |
| Steel rope | Diameter: from 8 mm to 40 mm; Type: 6x36 (IWRC, FC), 8x19; Length: according to the crane specification; Standard: DSTU EN 12385 | Ropes and slings |
| Limit switches | Type: roller, lever, end; Voltage: 24V DC / 250V AC; Degree of protection: IP65 | Electrical components and Automation |
| Crane hook (cargo) | Load capacity: from 1 t to 50 t; Material: steel 20G, 34KHN3M; Type: one-horned, two-horned; Standard: DSTU EN 13001 | Hooks and grabs |
| Bearings (for drums, blocks) | Type: roller, ball; Series: 222xx, 62xx; Manufacturer: SKF, FAG, Timken | Bearings |
| Contactors / Relays | Nominal current: according to the electrical diagram; Coil voltage: 24V DC / 230V AC | Electrical components and Automation |
| Fuses | Type: HRC, gG; Nominal current: according to the electrical diagram | Electrical components and Automation |
| Gear motor (complete) | Power: according to specification; Gear ratio: according to specification | Mechanical drives |
| Remote control (radio or cable) | Number of buttons, functionality: according to the faucet model | Management systems |
To order quality spare parts and components that meet CE and UkrSEPRO standards, visit the e-catalog UNITEC-D.
10. Links
- DSTU EN 15011:2018 Cranes. Overhead and gantry cranes.
- DSTU EN 12385-2:2018 Steel ropes. Security. Part 2. Definition, designation and classification.
- DSTU EN 13001-1:2018 Cranes. General provisions regarding construction. Part 1. General principles and rules.
- ISO 4301-1:1986 Cranes and lifting appliances — Classification — Part 1: General.
- Rules of labor protection during the operation of lifting cranes, lifting devices and corresponding equipment (NPAOP 0.00-1.01-07).
- Overhead Crane Operation Manual [Specify the model and manufacturer of your crane].
